Answer;
They will be 0.5x miles away from each other
Explanation;
Since the dog runs twice the speed of the cat
Its speed will be 2 * x = 2x mph
Now we want to know how far they will be from each other after 30 minutes
Kindly note that 30 minutes is 1/2 hour
Mathematically;
distance = speed * time
Distance of cat = x * 1/2 = 0.5x miles
Distance of dog = 2x * 0.5 = x miles
The dog is x - 0.5x miles = 0.5x miles away from the cat
